Transducers, such as acoustic transducers are employed by a vessel for mapping and locating. Transducers direct a number of streams of energy, such as sonar or other pulsed energy towards the bottom of the water while the vessel transverses the location. The transducer receives reflected signals from the water bottom, or an intervening object (such as fish, a diver, torpedo or submarine). The raw signal is translated and processed into a map of the water bottom, and/or the contents of the water. The systems are sometimes integrated with a navigational and guidance system, utilizing global positioning satellite (GPS) navigational technology, to provide accurate data and information.
In the past, transducers were hung over the side of or behind a vessel. This system has the disadvantage that the transducer is subject to noise from the vessel's engine and the turbulent movement of the water around the transducer and against the hull. Undesirable noise interference compromises the ability of the transducer to provide a clear and highly useable signal. Such mounting is also highly vulnerable to damage from floating objects, impact when docking, concussion from underwater detonation (such as mines) as well as stresses induced by the motion of waves.
More recently, thru-hull mounting of transducers has been utilized as an alternative. They have been typically limited to use with fiberglass and metal hulls, as wood hulls swell and shrink, inducing substantial stress and/or resulting in loss of mounting and waterproof integrity. Thru-hull transducer mountings are primarily retrofitted systems. The hull is cut to an opening sufficiently large to accommodate the transducer, which is then mounted flush with the use of a sealant and an optional isolation bushing. When a fiberglass hull is cut, the opening should be re-glassed and/or sealed in order to retain integrity of the hull near the cut. Changing and/or replacing a transducer frequently necessitates the hull be re-cut and the new or replacement transducer hacked into place. This requires that the vessel be dry-docked.
Most thru-hull transducer installations require a custom cut fairing as nearly all vessels have some dead-rise angle at the mounting location of the transducer. When a fairing and backing block is used to level the transducer the hull is still cut and raises the same concerns. The fairing and backing block are matched to a particular style and type of transducer. At the very minimum they are epoxied into place.
Thru-hull transducer installations result in weakened hull integrity, as well as make the transducers more susceptible to damage. Transducers such as solid-state phased array sonar as well as conventional transducers are damaged at significantly lower pressures than that required to buckle or cause failure in adjacent fiberglass or metal hull plate areas. Small explosive charges which are used for the purpose of blinding a vessel typically generate acoustic wave profiles sufficient to damage the transducer without damaging the hull.
Therefore, there is a need for a vessel hull transducer modular mounting system which enables transducers to be replaced and upgraded without necessitating the further modification of the hull and thus not necessitating the dry-docking of the vessel.